Background: Cubitus varus has long been considered merely a cosmetic deformity. The purpose of this paper is to demonstrate a causal relationship between cubitus varus and instability of the elbow.
Methods: In twenty‐four patients (twenty‐five limbs) with a cubitus varus deformity following a pediatric distal humeral fracture or resulting from a congenital anomaly (three limbs of two patients), tardy posterolateral rotatory instability of the elbow developed approximately two to three decades after the deformity occurred. All patients presented with lateral elbow pain and recurrent instability. The average varus deformity was 15° (range, 0° to 35°). Surgery was performed in twenty‐one patients (twenty‐two limbs). Treatment consisted of reconstruction of the lateral collateral ligament and osteotomy in seven limbs, ligament reconstruction alone in ten, osteotomy alone in four, and total elbow arthroplasty in one.
Results: In three patients, the triceps muscle was dynamically stimulated intraoperatively to contract while resisting extension of the elbow. This produced posterolateral rotatory subluxation of the elbow, which was reversed by corrective osteotomy and lateral transposition of a portion of the medial head of the triceps that originally had been attached to the elongated, deformed medial aspect of the olecranon. At an average of three years (minimum, one year) after the operation, the result was good or excellent for nineteen of the twenty‐two limbs that had undergone an operation; three limbs had persistent instability.
Conclusions: With cubitus varus, the mechanical axis, the olecranon, and the triceps line of pull are all displaced medially. The repetitive external rotation torque on the ulna permitted by these deformities can stretch the lateral collateral ligament complex and lead to posterolateral rotatory instability. Thus, cubitus varus deformity secondary to supracondylar malunion or congenital deformity of the distal part of the humerus may not always be a benign condition and may have important long‐term clinical implications. Operative correction can relieve symptoms of instability. The indications for preventive corrective osteotomy remain to be determined.
Shawn W. O'Driscoll, PhD, MD; Robert J. Spinner, MD; Bernard F. Morrey, MD; Mayo Clinic, 200 First Street S.W., Rochester, MN 55905. E-mail address for S.W. O’Driscoll: email@example.com
Michael D. McKee, MD; St. Michael’s Hospital, University of Toronto, Toronto, ON M5C 1R6, Canada
W. Ben Kibler, MD; Lexington Clinical Sports Medicine Center, 1221 South Broadway, Lexington, KY 40504
Hill Hastings II, MD; The Indiana Hand Center, 8501 Harcourt Road, Indianapolis, IN 46280
Hiroyuki Kato, MD; Hokkaido University School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo 060, Japan
Shinichiro Takayama, MD; Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160, Japan
Junya Imatani, MD; Okayama Saiseikai General Hospital, 1-17-18 Ifukucho, Okayama 700, Japan
Satoshi Toh, MD; Hirosaki University School of Medicine, 5 Zaifucho, Hirosaki, Aomori 036-8562, Japan
H. Kerr Graham, MD; Royal Children’s Hospital, Flemington Road, Parkville Victoria 3052, Australia